Locard's Principle
by Night Monkey
Summary: Sherlock sees young Archie for what he really is. A budding sociopath. In the following years, Sherlock does his best to keep Archie from slipping into darkness. Their tenuous balancing act threatens to topple when Jim Moriarty exerts his influence.
1. Hick's Law

I've watched _Sherlock_ basically since the beginning, but never wrote any fanfiction for it. Guess what's about to change! I was struck by a ten-ton plot bunny while watching _The Sign of Three_, and here's the result.

There are some spoilers for _The Sign of Three_ and _His Last Vow_, so you might consider seeing them unless you want some big surprises ruined.

* * *

It was two weeks after John and Mary's happy and eventful union, and Sherlock still couldn't get something out of his head. It wasn't the attempted murder of Major Sholto. Humans tried (and succeeded) at killing each other every day. Yes, the means was creative, but the motive was as old as mankind, and Sherlock had filed it away with every other case he'd taken and solved. It wasn't even the inexplicable bawling from the wedding guests that still played on Sherlock's mind. John had tried to explain sentimentality to Sherlock, and had done the best he'd could.

No, it was Archie, the little boy with the penchant for crime scene photographs.

Sherlock laced his fingers and rested his chin upon them.

Across from him, Archie did the same.

"I want to see the headless nun now."

"Wait until Mrs. Hudson leaves."

Archie glanced at the tea Mrs. Hudson had left on the table two minutes ago. "She's already gone."

Sherlock winked at the boy. Then, moving ever so silently, Sherlock rose from his chair and tiptoed across the room. He grasped the doorknob, turned it, and then flung the door open so violently it banged against the wall.

"Lose something, Mrs. Hudson?" Sherlock asked.

Mrs. Hudson gave a breathless little shriek and fell on her backside. "No- no, Sherlock. I was just-"

"Eavesdropping? Spying? Committing espionage?"

"You don't have to throw the thesaurus at me. I just wanted to make sure-"

"I wasn't corrupting minors?"

"Well, yes, a bit. You've got heads in your refrigerator, Sherlock."

"There's a liver and a set of kidneys in there, too. I won't tell you where I've hidden the appendix."

"He's five years old. His mother will kill you if he goes home and tells her about that refrigerator. She'll probably kill me, too."

"He isn't going to talk; he's not an idiot."

"Then he'll brag to his mates at school."

Sherlock snorted. "He hasn't got 'mates.' The other children think he's defective."

"They don't even know that word, Sherlock."

"They know how to ostracize someone who's cleverer than them."

Mrs. Hudson sighed. "Just don't blow-torch any eyeballs around him. It stunk for days last time you did that."

Sherlock snapped to attention and gave her a military salute. Mrs. Hudson shook her head but turned away and headed downstairs. Sherlock waited until her footsteps faded completely before slamming the door and returning to his chair.

Archie hadn't moved, which even the thickest of adults would have found odd. Here was a boy in a strange house, in a room full of objects that begged to be dropped, broken, fondled, stolen, or possibly ingested, and he'd been left unsupervised. He hadn't even been told to sit still and behave. So why wasn't the room in shambles?

"You are a sociopath."

"What's that?" Archie asked.

"Someone like me."

"A detective?"

"Rarely. Usually the opposite."

"A bad guy?"

"You could be. Like Moriarty."

"Who's that?"

Sherlock strode around the room, grabbing things seemingly at random. A laptop. Folders. Newspaper clippings. A magazine. Photographs held bundled together with paperclips. When his arms were loaded, he returned to Archie and spilled the mess out on the table, where it mingled among the tea cups.

"This is Moriarty." Sherlock handed the magazine to Archie. The cover of the magazine was simple. A man, black hair and dark eyes, wearing the crown jewels. The picture had obviously been taken from security footage.

Archie giggled. "He looks like a king."

"He was, in his own way."

"I like his crown."

"He's dead now."

Archie showed absolutely no reaction. He reached a hand out and touched Moriarty's crown.

"He put a gun in his mouth and blew the back of his head off."

"But he got to be a king first."

Sherlock replaced the magazine with a sheaf of photographs. Archie's eyes lit up. "Is the headless nun in here?"

"No, these are Moriarty's victims."

Archie flipped silently through the pictures. Sherlock watched him intently, waiting to see _something_ cross the boy's face. Shock. Horror. Fear.

Admiration.

"All these people?" Archie finally asked.

"Not directly. Sometimes Moriarty hired people to do it. That first lot, they were poisoned by a very sick man Moriarty paid to kill people. Because it was funny to Moriarty. He liked to make people do awful things," Sherlock explained.

"Wicked. Did Moriarty kill the headless nun?"

"Afraid not."

"This is cooler anyway."

"You're right. Besides being a nun and being headless, there wasn't much more to her. Here there's plots and subplots. A tangled web across continents. Much...cooler."

"Sherlock! Archie's mother's coming in!" Mrs. Hudson yelled from downstairs. "Hide the heads!"

Sherlock gathered up the assorted Moriarty memorabilia and dumped it atop a stack of who-the-hell-knew-what. It was now perfectly camouflaged to any outside observers. After hiding the incriminating photos of dead women and exploded buildings, Sherlock hopped back into his chair and opened the laptop. The screen turned on and a perfectly child-friendly police safety video about not talking on your mobile while crossing the street began to play.

The door opened and Archie's mother took a tentative step into the room. "Boys? Did you have fun?"

"Can I finish watching the police video?" Archie asked.

"Okay, if it's not much longer."

"Only five minutes," Archie replied.

"Headless nun next week, I promise," Sherlock whispered.

"What was that?" Archie's mother asked.

"Oh, field trip next week. We're going to identify pollen from different areas of the city. Invaluable in crime-solving," Sherlock said.

"You're learning so much with Sherlock. You're going to be the most clever boy in class."

"I'm sure he already is," Sherlock said.

The video ended and Sherlock handed over his young associate. "See you next week, Sherlock."

Sherlock closed the door behind Archie and his mother. The detective then lingered, listening to their footsteps. Once he was sure Archie hadn't forgotten anything or his mother wouldn't come back and try to pry, Sherlock returned to the stack of Moriarty articles and crime scene photos.

Only the sneering face of Jim Moriarty had been replaced with the much younger face of Archie. Sherlock grimaced and turned the magazine over, blocking out its cover and every other image of the maniac.

* * *

_Five Years Later_

"What happened to your arm?"

"I broke it."

"How?"

"I was thrown out of a window and landed on a car."

"Did it hurt?"

"I was _thrown out of a window_ and landed on a _car_."

"You don't have to be sarcastic."

"And you're too clever to be asking stupid questions."

Archie punched Sherlock in the cast and bones set just a day before shifted. Even for someone who'd been beaten, strangled, shot, defenestrated, and generally injured on the job as much as Sherlock, jarring a freshly broken arm was painful enough to make him gasp.

"Don't call me stupid."

"I was calling your question stupid! And I think you've got enough evidence now to know whether or not it hurt!"

Archie glared at Sherlock. Sherlock returned the glare.

"What are you two fighting about?"

Mrs. Hudson, tea tray in hand, stood in the doorway.

"Staring contest," Sherlock replied stiffly. "Set the tea over there and don't distract us."

"You could say 'please' every now and then, Sherlock."

"Fine. _Please_ set the tea over there and _please_ don't distract us."

Instead of doing as Sherlock asked, Mrs. Hudson bustled between Sherlock and Archie and completely blocked their view of each other. "You weren't having a staring contest; you were fighting with a ten-year-old. Honestly, Sherlock, sometimes it's a wonder Archie wants anything to do with you."

Sherlock's mouth fell open. "He started it!"

"I knew it! I knew you were fighting." Mrs. Hudson turned to Archie and gave his head a sympathetic pat. "Don't worry, dear. Sherlock's never known how to act his age."

Mrs. Hudson set the tea tray on the table and, with one more warning glance at Sherlock, departed.

The minute she was gone, Archie gave Sherlock the single smuggest grin the detective had ever seen. Sherlock snorted. "You won't be cute enough to get away with everything for very much longer. Enjoy it while you can."

Archie smacked Sherlock on the cast a second time.

"Mrs. Hudson! He's starting again!"

* * *

_Five Years Later_

Archie was still enjoying it. Sherlock could tell just by looking at him. Puberty hit most children like a freight train, and the results were ghastly; Archie had enjoyed all the benefits of the hormone stew, and had suffered only a brush with the nastier effects. He'd sprung up almost overnight and now stood taller than John, and was quickly sprouting after Sherlock. He had only a few spots of acne on an otherwise handsome face. He'd gone without shaving that morning, but on purpose, because he'd taken the time to comb his hair and otherwise groom. Said hair was still the dark brown of his childhood, though it was now much shorter and tamer.

"I thought you'd forgotten about me," Sherlock said.

"I've been in France with my dad for the summer holiday. I called. Sent texts. Emailed."

"I was on holiday as well. Moriarty locked me in a cage. In an actual dungeon. It took me three weeks to escape. How did I do it?" Sherlock asked. This was an old game of theirs, one Sherlock had started ages ago. He'd go somewhere or do something, usually not something as exciting as being held captive by his arch-nemesis, and then leave subtle clues for Archie to unwind.

Archie stood and began to slowly walk around Sherlock. He examined Sherlock's hands. Lifted the detective's head and none-too-gently pressed on the fading bruises that circled Sherlock's throat. He then squatted down and looked at the soles of Sherlock's boots.

"There were rats involved. You must have picked them up at some point, because those are rat bites on your hands. They're deep, there are a lot of them, but they're all at the same stage of healing."

Sherlock nodded. "I made a lock-pick out of rat bones. The rat wasn't very eager to aid my escape."

"You were caught. A guard or someone put you in a headlock. You kicked him with your right foot. That boot's scuffed but the left isn't. You took the guard's weapon and dealt with anyone else who tried to stop you."

"And how do you know that?"

"Because you have a brain and it's what anyone with a brain would do. And also because the knuckles of your trigger finger are bruised, suggesting you fought over the gun and barely came away with it."

"And how did I return to Baker Street?"

"Stole a car. The keys are in your pocket," Archie said.

"Perfect." Sherlock applauded.

"And what about Moriarty?"

"Did I catch him, you mean? No. Your hero is still out there," Sherlock replied.

Archie fidgeted. "He isn't my hero."

"You've got his hair style. And his five o'clock shadow. If you had the money, you'd have his Westwood, too."

There was no accusation in Sherlock's voice, no hint of anger or betrayal or offense. Simple evidence. Like cat hairs on a jacket or lipstick on a collar.

"He isn't my hero," Archie repeated.

"Your idol, then."

"You're my idol."

Sherlock shook his head. "I was never your brand of sociopath."

"I've been visiting you, learning from you, since I was five years old! If you weren't my 'brand of sociopath' why would I waste so much time with you?" Archie demanded.

"Because I am the best substitute you could find. I was the only one who could understand you. Understand what it felt like to have no friends because all your classmates were gibbons by comparison. To look at your parents and to wonder how that ever produced you. And to look at this, and to see meat."

Sherlock threw the picture of the headless nun on the table.

"And because I could give you this, and it could be our secret. That's why you're really here. Not because after three weeks with your father, you were starving for intellectual conversation. But because you've gone three weeks without seeing anyone separated from their head."

"That's disgusting and you are completely full of shit. I was a kid and I was curious. And maybe a little morbid. A lot of boys are."

"How many little boys pretended to be sick the day Jim Moriarty came back from the dead, just so they could stay home from school and watch him repeat the same four words on every station?"

"How'd you know?"

"'I was worried Archie was coming down with something. He was too sick to get off the couch last week. He seems fine now, though.'" Sherlock upped the pitch of his voice and did a half-decent impression of Archie's mother.

"You remembered something my mother said ten years ago?"

"I remember things the postman said thirty years ago."

Archie drew in a deep breath. "I always did want to meet him. Still do. I'd kill for the chance. Maybe literally."

"I tried," Sherlock said abruptly. He was suddenly out of his seat, pacing. "Tried to interest you in my job. And I did. A little. Didn't I? But collecting dandelion pollen and brick dust wasn't enough. Blood spatter analysis wasn't enough. Flogging corpses wasn't enough. _I _wasn't enough. I couldn't compete with Moriarty. Or with your genes. So nature and Moriarty win."

"Sherlock-"

Sherlock spun around, his coat billowing out. "I failed. I was inadequate. There is blood on your hands. Left hand, a smudge under the nail of the index finger."

Archie was silent for a moment. "It was a cat. I needed it after three weeks with my dad. It was a cat, or it was him. I chose the cat."

"This time."

"Are you going to tell anyone?"

"Of course not."

"Thank you. I won't do it again."

"No, you will. You'll just wash up better."

"Thanks for the vote of confidence, Sherlock. My mum's probably getting worried. See you next week. If I don't kill anyone by then."

Archie rose from his armchair and without so much as a backwards glance left the flat. Sherlock stayed standing. He wasn't going to tell anyone, not even John. This was his mess, and he had to contain it. If he couldn't, he'd clean it up himself.

* * *

TBC


	2. Laws of Robotics

Thank you all so much for the reviews. I was all kinds of nervous publishing this, and you've given me a big boost of confidence.

* * *

_The Next Day _

Sherlock paid a visit to John, Mary, and their monkeys. Or children, as John and Mary preferred the screaming, stinking, biting little humanoids be called. The children were particularly unevolved that day, so by the time Sherlock was able to slip out the door, he was wearing three different kinds of food and and had some sort of paste in his hair. Oh, he also sported a bright blue mustache, a pink unicorn, and a grotesque monster that was supposed to be a sheep but looked more like the Baskerville hound, all drawn in what Sherlock prayed to a god he didn't believe in was washable marker. Otherwise he was never going to be able to leave his house again.

"Oh, Sherlock-" Mrs. Hudson began when the detective banged into the room.

"Not now, Mrs. Hudson, I have to bathe."

Sherlock stomped up the stairs, rubbing furiously at the mutant sheep on his hand as he went.

"You've got a guest!" Mrs. Hudson shouted up after him.

Sherlock grunted and opened the door to his apartment. The lights were on. Sometimes he left them on when he went out, but this wasn't one of those times. Sherlock scanned the room, looking for whoever was wasting Mrs. Hudson's electricity.

A young man with sandy blond hair was seated in Sherlock's chair. The detective paused and narrowed his eyes at the stranger.

"You dyed your hair," Sherlock said.

"And let me guess: you don't like it."

"It's your father's hair color."

"I've hung out with you for ten years and it's still creepy how you can do that."

"You're making amends for something he'll never know you did."

"I know, but I've been thinking about yesterday. I really didn't want to kill my dad. I don't want to kill _anyone_."

"Except sometimes you do."

Archie took a deep breath. "Except sometimes I do. Yeah. But I can't. You've got to help me."

Sherlock raised an eyebrow. "I'm a consulting detective. People seek me out _after_ a crime been's committed."

"This'll be way more challenging. Stopping a murder before it ever happens. Sort of _Minority Report_."

"What's that?" Sherlock asked.

"A movie where, in the future, they can predict murders before they ever happen, and arrest killers before they ever kill."

"Are they really killers then?"

"I dunno. I mean... I dunno. You never taught me how to deduce stuff like that."

Sherlock and Archie both fell silent. Still without a word, Sherlock crossed the room and extended his hand to Archie.

"I will never dedicate myself more to a case," Sherlock vowed. Archie took the offered hand and shook for all he was worth.

* * *

_Two Months Later_

"Sherlock! You can't bring bloody minors to crime scenes! Especially not murder scenes! And especially not this one!" Lestrade cried.

"He's seen the photos since he was five," Sherlock replied.

"Oh my God, don't tell me things like that!"

"Let him through or I'm going home to watch daytime television and melt femurs in my bathtub."

Lestrade sent a silent prayer to any God or gods he could think of that nobody in the media snapped a picture of a teenager trampling all over the crime scene. With a wave of his hand, Lestrade signaled the officer who was holding Archie back to let him through. The officer gave Lestrade an incredulous look, and all Lestrade could do was shrug his shoulders.

Archie darted around the officer and joined Sherlock corpse-side.

The corpse was a young woman, or what remained of a young woman after she'd been partially dismembered with a saw.

"What do you see?" Sherlock asked.

"The killer took off the hands and head. Obvious thing to do if you don't want someone identified," Archie said.

"Right, no fingerprints or dental," Lestrade said.

"Thank you. Couldn't have figured that out ourselves," Sherlock responded loudly, and Lestrade blushed.

"Anything else?"

Archie crouched down next to the partial corpse. "The hands and head are obvious, but why take one hand off at the wrist and the other at the elbow? There had to be something different about the arm. A mark or...a tattoo!"

Sherlock applauded, the cheerful sound making several of the officers more than a little uncomfortable. "There you have it, Lestrade. The victim had a very unique tattoo on her left arm. And the tattoo must tie her to her killer. The tattoo artist? No, don't think so, why make her so identifiable in the first place if you're only going to kill her? You!"

Sherlock whirled around and pointed at an officer on the perimeter. The officer stared at Sherlock with horrified eyes.

"Me? I didn't kill her!" he protested.

"I _know_ that. Come here."

"But I've got to hold the perimeter."

"Because a horde is trying to descend upon us."

The officer looked at Lestrade and silently begged for help. Lestrade sighed and again was forced to shrug his shoulders. Forsaken, the officer plodded over to Sherlock.

"It's warm today, and you're one of two people with their sleeves rolled down completely. I am the other, since I'm sure you were wondering and didn't notice yourself. The question is, why? My answer, you have ink you don't want to share with the class."

Sherlock grasped the officer's right shirtsleeve and pushed it up past the elbow. He revealed a Chinese character tattoo.

"Not what I'm looking for. And not what you were looking for, either."

"Eh?"

"Terrible translation," Sherlock replied. Without further elaboration, he rolled up the opposing sleeve. This time the revealed tattoo was a badly faded band logo.

Not bothering to ask for permission, Sherlock lifted the officer's shirt and draped it over his head. The blinded cop moaned piteously. Sherlock spun him around and then exclaimed, "There it is!"

"What? Can I wear my shirt like a human being yet?"

"Only once you tell us who Sheila, Amanda, and, Archie, what does this say?"

Archie walked over, turned his head sideways, and squinted. "Hmm, Gary?"

"Grace! Her name was Grace! They're old girlfriends, alright?"

"There's the answer. The victim tattooed her killer's name onto her arm. Probably because her brain was full of serotonin and oxytocin, not because she believed he was dangerous. They had a fight about something, likely the brand-new tattoo, and he killed her. Find the shop where she was tattooed, and you'll find the name of your killer," Sherlock said. "You'll also get a name for the victim, unless the tattoo artist was painfully ignorant."

"You've done fantastic work, Sherlock, but do you think you could narrow it down a bit more? There are dozens of tattoo shops and-"

"And you can't be arsed to figure it out yourselves," Archie muttered.

"Then figure it out for them," Sherlock whispered back.

Archie bent down and looked the body over. He took in the clothes and shoes. Heads and hands were a treasure trove of information on a person, but even without those, it wasn't impossible to get a fix on someone. In this case, the clothes alone were plenty to go on.

"She was at a club last night. Some stupid, poncy one. Her dress and shoes are expensive, designer stuff. They just _look_ like hooker clothes," Archie said.

Sherlock couldn't hide a grin. Not the best way to phrase it, but Archie had noticed the labels. Good.

"And she was plastered. Literally falling-down drunk. Skinned her knees. And she still smells like alcohol."

"So a tattoo shop near a club? That's got to narrow it down. Someone pull up a map and-" Lestrade was cut off.

"He isn't finished," Sherlock snapped.

"I'm not?" Archie asked.

Sherlock shook his head. "You can give them a name."

Archie attacked the body with new intensity. No hands, no head. Blood everywhere. Odor of alcohol. But what kind? How the hell was Archie supposed to know? He'd nicked beer once in his life! Sherlock had to know that; Sherlock knew everything. So what was-

"There's blue on her. And purple. She spilled her drink down the front of her dress," Archie said.

The dress was black and had absorbed every drop that had fallen on the fabric, but there were still slight stains in the dead woman's cleavage.

"Blue and purple? That's an Aurora! Like the Northern Lights, you know?" the officer with the shirt over his head and the terrible tattoos said.

"So it's a specialty drink? From where?" Lestrade asked.

"Place is called Juneau. And it is stupid and poncy. Broke up with my last girlfriend there because I wouldn't pay for her drinks. Bloody outrageous prices," the officer said. "And before any of you ask, no, I haven't got her name tattooed somewhere."

"You've earned the right to put your shirt back on," Sherlock said.

The officer did just that. While he straightened his shirt, Sherlock clapped Archie on the back. "They can handle it from here."

"They can?" Archie asked.

"I am at least 51% certain. And if they can't, then they should all be sacked!" Sherlock said this loud enough for everyone, including the few curious onlookers, to hear.

While the police hurried to locate a tattoo parlor on the same block as Juneau, the over-priced dance club with the colorful drinks, Sherlock escorted Archie off the premises. As they walked, Sherlock pounded out the last few details.

"She's rich, he isn't. I'd also wager a criminal background. All the more reason to keep him secret," Sherlock said. "Last night, probably into early this morning, she consumed enough alcohol to make John's bachelor party look sober. Continuing a long line of bad decisions, she staggered into the nearest tattoo parlor and made a very permanent declaration of love."

"Which led to her being chopped into pieces and dumped outside a crack house," Archie finished.

"Astutely observed."

"Thank you."

"Now let's go back to Baker Street and teach you how to identify alcohol."

* * *

_One Year Later_

"Any good cases?"

Sherlock, his deerstalker pulled down over his eyes, grunted.

"Any not-completely-simple cases I could work on?"

Sherlock grunted again.

"You didn't have a stroke and now you can't talk, did you?"

"Meh," Sherlock said.

"That's still basically a grunt."

"Nothing. No Triad assassins, no forged artwork, no military experiments with glowing bunnies! Dull, dull, dull!"

"Shit."

Archie hopped into the armchair opposite of Sherlock's slumped, anti-social form. "Someone had better commit some better crimes."

Sherlock stiffened and had no response, caveman grunt, frustrated outburst, or otherwise.

"I didn't mean _me_. That wouldn't be a challenge for either of us, because we'd both know who did it."

"There might be hope yet," Sherlock said. So little hope he didn't bother taking off his hat or uncoiling from his scrunched position.

"Another consult?" Archie asked.

"Five minutes late."

The doorbell rang downstairs. Sherlock was too consumed by ennui to bother walking down to answer it. He was even too bored to shout for Mrs. Hudson. Archie finally took the initiative and went to fetch the potential (but highly unlikely) client.

Three minutes later, Sherlock, who had just enough consideration to sit up and pay marginal attention, faced the client. It was an elderly man who believed his wife had been stealing from him.

"But she's been dead for two weeks."

"I think it's her ghost. Jane was always so protective of her things, and since she's passed on, I have moved a few of them around."

"A thieving ghost? That isn't my area of expertise. Why don't you try- Archie, what's that show with the aliens?"

"_The X-Files_," Archie provided.

"Someone is taking my property, and it isn't damned aliens!" the man shouted.

"It isn't a corpse either! It's your daughter! Your wife cut her out of the will, so she's taking what she feels she deserves. Go sue her and leave me in peace!"

The old man's jaw dropped open. "But- Eliza wouldn't- How did you know about the will?"

"Your daughter slapped you hard enough to leave a bruise. It's a fresh contusion, and would coincide with the reading of the will," Sherlock explained.

The old man brought a hand up to his cheek. "But I keep my doors locked."

"Did your daughter ever live in the house with you?" Sherlock asked.

"Yes, her whole life, until she was 20 and moved in with her boyfriend."

Sherlock rolled his eyes. "Then she probably knows a dozen ways to enter and exit without leaving any traces. Check her bedroom window first."

The old man moaned and began to cry. Most human beings would have offered him a hug and a shoulder to cry on. Sherlock rolled over and pulled his deerstalker back over his eyes.

Archie was left completely trapped. He wasn't very good at comforting people, but he also didn't think turning his back on the old man was an acceptable answer. It was alright for Sherlock, because that was what Sherlock did when he was sulky, but Archie hadn't earned the right yet.

"It's alright. Come downstairs and Mrs. Hudson will get you some tea and phone for a cab," Archie said. There, that was the solution! Passing it on to Mrs. Hudson.

Using Archie's arm as support, the old man limped out of the room. Mrs. Hudson was used to Sherlock's rejected clients leaving in all manner of distressed states, though sobbing and relying on Archie just to stay upright was relatively uncommon. Mrs. Hudson ushered the old man to the table, where she began to fuss and coo, which was just what the poor fellow needed.

His charge delivered into safe hands, Archie slipped out of the room and jogged back upstairs. Sherlock, surprise, surprise, was still curled into a bored, grouchy ball.

"Is he gone?" Sherlock asked.

"Gave him to Mrs. Hudson. She's good with human stuff." Having made his report, Archie sat down in the armchair next to Sherlock's.

"I'm dying," Sherlock said.

Archie whipped around to gape at Sherlock. "What?!"

"Of boredom! It is killing me! Nothing remotely interesting in two weeks! I need to smoke!"

"No."

"Yes!" Sherlock roared.

"I'll call John and Mary and Mrs. Hudson if you try."

"Then I will leave, and smoke in private."

"That won't stop me from calling them. And if you're missing, they'll probably call your brother, too."

Sherlock snarled in frustration, and at the mention of Mycroft. "Where are my nicotine patches then?"

"How many are you already wearing?"

"None of your bloody business!"

"Then I'm not letting you have another one."

Sherlock rolled off the chair and stormed towards the kitchen. Archie didn't bother following. There was nothing stronger than coffee in there, and coffee was exactly what Sherlock had decided to settle on.

After much banging, growling, and incoherent raving, Sherlock returned with coffee. An entire pot of it. Knowing Sherlock, he'd probably dumped half a bag of sugar into the pot.

"That's probably gonna give you a heart attack," Archie said.

"Good. I have it on very good authority that I'm going to love being dead. When you're dead, no one ever bothers you."

"Where'd you hear that?"

"From Moriarty."

Sherlock sipped the coffee. No matter how much he wanted his caffeine fix, biology prevented him from chugging coffee that was just below the boiling point.

"You've got to share," Archie said. He went into the kitchen and returned with two mugs.

"Mine," Sherlock replied.

"This counts as self-destructive, and I'm definitely supposed to tell John if you do anything like that."

Sherlock stomped, actually stomped, across the floor and back into the kitchen. He poured the coffee down the sink. "There. Now no one gets any."

"That's really mature."

"I still haven't learned to act my age. Which is a good thing. Otherwise I'd be doddering around, getting fat, while my offspring attacked my best friend."

Archie laughed. "You really suck at dealing with kids."

Sherlock cracked a smile. "I know. I'm not allowed to watch _Doctor Who _with John's children anymore. Apparently you aren't supposed to root for the Cybermen."

Before Sherlock could dive into why being a robot would be the best fate he could imagine, his phone buzzed in his pocket. He yanked it out and looked at the screen. It displayed Lestrade's number. Sherlock tried not to get his hopes up. If this turned out to be some _boring_ crime of passion or gang murder, Sherlock was going to start climbing up the walls.

Sherlock connected the call and put the phone to his ear. Instead of a standard greeting and inquiry about the state of Lestrade's life, Sherlock said, "Please tell me it's a serial killer."

"It...might be. It's definitely something. The thing is, we can't figure out how many bodies there are."

Sherlock's eyes lit up and he bounded out of the chair, completely re-energized. "Where are you?"

Lestrade gave him an address and Sherlock pulled up his mental map of London. The address was on the bank of the Thames, which brought all sorts of delicious implications. Bodies that had been submerged always brought an additional challenge, and that was exactly what Sherlock needed.

"Is it a case?" Archie asked.

"We'll know soon enough," Sherlock replied. "The game is on!"

"Hopefully."

"Hopefully."

* * *

TBC


	3. Lanchester's Square Law

Thank you all so much for the reviews!

* * *

Sherlock had been to hundreds of crime scenes in his life, but the moment he arrived, he knew this one was special. The body count alone made it stand out, and the condition of the bodies was likewise unique. No, Sherlock amended, he _had_ seen people killed in each of the manners displayed. Just never all dumped together like this.

"No, Sherlock, no. I am putting my foot down here. He can't see this," Lestrade said.

"He's seen the aftermath of guns, acid and suicide bombings," Sherlock replied.

Lestrade somehow went even paler. "You've got to be breaking some laws, showing him that!"

"I only showed him the first two. He found the last one on Google by himself."

"But this is real life, not something online. It could scar him," Lestrade protested.

"No, it really can't," Sherlock replied.

There was no arguing with Sherlock. As much as he didn't want to, Lestrade had no recourse but to let Archie onto the scene. It was that, or risk losing Sherlock's help. And they sorely needed help with this one. There was not an officer on the force who would argue otherwise.

"Alright, Sherlock. Just tell us what happened here. You, not him. He's an observer only. And don't observe too closely!"

Archie had been crouching down to examine a severed hand. He quickly straightened up.

"First off, you have six bodies," Sherlock said.

"You're sure?" Lestrade asked.

Sherlock rolled his eyes and pointed at the hand Archie had been looking at. "That's a left hand. The right is over there, next to the sniper victim. Two hands, one body. Sniper lady, that's two."

"That is not an official designation of the victim! Do not refer to her in any reports as 'sniper lady'!" Lestrade said to his officers.

Sherlock continued, "Third body, it's...basically everywhere. Bomb victim. Improvised device, lots of shrapnel. Not detonated here or anywhere in the vicinity, as none of the other bodies are full of ball bearings and nails. Fourth body, beheaded. Fifth body, the only one not visibly marked. Except for that drop of blood on his collar. He was injected with poison. Sixth body, garroted, a classic and one of my favorite."

"And you're sure that mess is two people? Not one, not three, two?" Lestrade asked.

"Explain it to him, Archie," Sherlock said.

Archie hopped to attention. "They were killed in really different ways. See the hands and these other bigger bits? They're clean cuts. Yeah, there's lots of pieces, but they're uniform. Cut at the joints, places that make sense. The bombed guy, he's chunks. And I don't think he's all here. There really isn't enough for one person, never mind two."

An officer clamped a hand over her mouth and bolted from the crime scene. Lestrade, defying the laws of nature, managed to drop to an even more pallid level.

"I am very, very concerned about you," Lestrade said. "I think you should talk to someone."

"He's fine! There's nothing wrong with him!" Sherlock barked.

"You, too, Sherlock. We've got people in the department who-"

The glare Sherlock gave Lestrade could have melted glass. The inspector dropped the issue and then punted it for good measure.

"Right, not important just now. Bigger fish to fry. Why are six people killed in six different ways all piled up here?"

"I have good news and bad news about that," Sherlock said.

"Bad news first," Lestrade said. A few of his fellow officers mumbled disagreement, but he was the boss.

"It's not a serial killer," Sherlock said.

"How is that possibly bad news?"

"Because it's _six _serial killers."

Lestrade swore he felt his heart stop for a moment. He'd read about such things happening in novels, but he'd never really experienced it firsthand until right then. It did indeed seem like his heart was wrestling with Sherlock's words and was deciding whether or not to keep beating.

"The good news?" Lestrade finally wheezed, a hand on his chest.

"They aren't doing this for fun. You haven't got Jack the Ripper on your hands. These corpses are resumes."

"Resumes? Like for a job application?" one of the cops asked.

"Exactly."

"But who would hire six killers?"

"Moriarty!" Archie exclaimed.

"No," Sherlock said.

"No?"

"No. He isn't hiring six. He's hiring _one_. These are try-outs. Best killer wins, gets to join Moriarty's team."

"Any idea who's in the lead?" Lestrade asked.

"Not the sniper. That's a rubbish shot. He was either going for right between the eyes or dead-center of the forehead, and ended up almost in her hair."

"How do you know that wasn't the intention?"

"Because there's no theatricality to that. These people are trying to impress James Moriarty! Do you think he'd be satisfied with anything except a perfect trick shot?"

"Probably not, but I've never met the man. Alright, if not the sniper, who? The bomb's...impressive."

Sherlock looked at the scattered bomb victim. "Big fish in a big pond."

"What's that supposed to mean?"

"It's painfully easy to build a bomb. Even a bomb this destructive. Moriarty could have dozens, possibly hundreds, of terrorists do the same thing. It's generic. He'd want someone unique, someone with a singular skill set," Sherlock explained.

"Dear Lord. So snipers and terrorists aren't good enough for Moriarty. Sherlock-" At this point, Lestrade leaned in close, so only Sherlock could hear him "-we're out of our depth here. If it was one nutter with a vendetta we could manage, put out alerts, but for this, for anything dealing with _him_, we need you."

Sherlock nodded. "Yes, you certainly do. And unless you've got another body hiding around here, Archie and I should be off trying to find him before round two starts."

"No, that's all of them. And I certainly wouldn't want anymore, thank you very- What do you mean by round two?"

"You are the weakest link. Good-bye," Archie said.

"Exactly. They've put their talents on display with civilian targets. Now the game gets serious. They'll turn on each other, and the last man standing gets the prize," Sherlock elaborated.

"They're going to turn the city into a war zone! Sherlock, what are you standing around here for? Go!" Lestrade cried.

* * *

_One Hour Later_

For the low, low price of ten quid and a sandwich, Sherlock and Archie were escorted to a dead man in a bell tower. The member of Sherlock's homeless network, after receiving her payment and pointing up the stairs, was quick to be off.

"Something's got her knickers in a twist," Archie said.

"Probably the state of whoever's up there," Sherlock replied.

The pair ascended the creaking stairs, with Sherlock in the lead.

"We should have guns," Archie said. "We're hunting bombers and snipers."

"John doesn't like it when guns and I mix."

"'Cause of that guy you shot, the blackmailer?"

"Exactly. Though what John doesn't know won't hurt him. At least in regards to this. John not knowing a gang of Chinese criminals wanted to capture me did almost kill him." Sherlock pulled a gun from his coat.

"You haven't got a spare for me, have you?"

"Nope."

"And I should take it as the end of the conversation, right?"

"Yep. Oh, look, it's the sniper. And there's his head on the window sill."

Just as the homeless woman had said, a body, a huge pool of blood, and a rifle rested at the top of the stairs. The head, however, rested just a little higher. The head was turned outward, as though it was looking over the city.

"One down," Archie said.

Sherlock grunted in reply and knelt down by the corpse. He could tell with only a cursory glance that whoever had beheaded the body at the earlier crime scene had also beheaded the sniper. The repeated hacking evident on the neck suggested nothing as sharp or polished as a sword, but a heavier weapon like a machete.

"Cartel," Sherlock said.

"Like with drugs?"

Sherlock nodded. "My first guess would be out of Juarez, in Mexico. The cartels there have a nasty habit of cutting off the heads of law enforcement, rivals, anyone who stands in their way. Whoever is responsible for this mess is probably a top enforcer looking to move up even higher in the world."

"And the sniper didn't hear him coming?"

"You know better. Look at the evidence," Sherlock replied.

Archie did just that. He took in the body, the gun, the blood splatter. Together they told him the story. There was a single defensive wound on the body, a deep cut that bit halfway through the wrist. The rifle was far out of the corpse's reach, and the barrel had been gouged. It had obviously been knocked away with a heavy swing of a bladed weapon.

"He did hear the killer, just too late."

"Though considering how arthritic those stairs are, we should assume the killer does possess some stealth."

Archie agreed. The stairs did creak like old people's joints, and anyone who wasn't totally deaf would have heard them. Besides, it added to the narrative and explained how a cartel hitman armed with a machete could compete with terrorists.

"What should we do now?" Archie asked.

"Call Lestrade. Let him get that head picked up before a gust blows it out the window," Sherlock replied.

Archie pulled out his mobile and dialed the inspector's number. By the time the police arrived, Sherlock and Archie were long gone.

* * *

_The Next Morning_

The police had found the garroter. Someone, presumably the bomber, had blown up him and his car, and then dropped a garage on him. His neighbors weren't happy to be woken up at the crack of dawn by an explosion, and they were even less pleased to discover a man they'd all generally liked had been a freelance serial killer.

"He was in my kitchen just last week! Jesus Christ, I baked him a pie!"

"But he seemed so...normal. Not like he had a dungeon or anything like that."

"That's because he didn't have a dungeon. Who said anything about a dungeon? There was no dungeon found on the premises," Lestrade protested to the crowd. "Once again, no dungeon!"

"I bet he killed them in his shed, then. Awfully big shed for such a little garden."

Lestrade wished he could transport the crowd of neighbors to the moon. Things were already going to be difficult enough to explain—a suspected serial killer dying in a car bomb was sensational enough—without having to add any more vulgar or sordid details like torture dungeons to the equation.

Sherlock chose just that moment to pop out of the shed and proclaim, "This is where he murdered her." He was holding a length of rope and two black gloves. Lestrade wanted to shoot him.

"Sherlock, inside, _now_!" Lestrade barked.

The only place Lestrade could have it out with Sherlock without every cop and civilian seeing was inside the late garroter's house. His garage, mercifully, hadn't been connected to the house, so the explosion hadn't done more than singe the paint on the side of the house nearest the explosion.

The consulting detective was relieved of his evidence by two police officers and their evidence bags before he followed Lestrade into the house.

Lestrade found a room not currently swarmed by forensics, and ushered Sherlock inside. He then closed the door. Sherlock immediately began to search the room.

"Sherlock-"

"This drawer has a false bottom."

"That's very nice, but it's going to wait. You need to be more careful-"

Sherlock pulled the drawer from the dresser, tipped it upside down, and rained the dead serial killer's socks all over the place. He fiddled with the drawer until the false bottom sprang open. Then a rain of documents fell atop the sock pile.

"I can't properly shout at you if you're solving this," Lestrade said. "What do we have here?"

"Passports, drivers licenses from three different countries, oh, and currency from the same countries. Someone's been on a hell of a holiday." Sherlock held up Norwegian 500 kroner note and a French drivers license.

"Do you suppose- Of course he has. A tourist serial killer. Interpol's going to need to hear about this. I've got some good mates in France, might call them directly and ask if anyone's been garroted lately," Lestrade said.

"Best of luck with that. Archie and I will see if we can't trace the bomb."

"Oh, good, that would be an enormous... Wait, Archie's here somewhere?"

"Left him in the shed."

Lestrade wanted to cry.

* * *

_Five Hours Later_

Bombs were like fingerprints, in that no two terrorists had quite the same technique. And while the differences between bombers could be subtle, for someone who knew what to look for (like Sherlock Holmes, for instance), there was always a signature to find.

In this case, after going over the ruined garage, charred car, and obliterated garroter, Sherlock had pieced together both the scenario and the materials used to make the bomb. The bomber hadn't actually planted the explosive on the car; the garage had instead been rigged. The bomb had been wired into the automatic garage door opener. When the garroter had activated the door opener with his remote, he had also activated the bomb's first switch, priming it to explode. Once he was parked inside the garage, he had used the remote again, this time to close the door.

And inadvertently blow himself into oblivion.

It was ingenious.

And it gave Sherlock a lot to consider. The bomber, whoever they were, was one clever, brave bastard. They had somehow discovered the garroter's home residence, perhaps by following him, and had, while the garroter was out doing whatever all night (Sherlock fully intended to figure out that "whatever") crept into his garage, wired it to explode, and then snuck out again. All with the possibility of being caught in the act dangling over their head like an Acme anvil.

Maybe Sherlock had written off the bomber too quickly. Big fish in a big pond might not have covered it. Great White Shark in a big pond was more accurate.

"Sherlock. Hey, Sherlock!"

Sherlock was distantly aware of someone tugging on his arm. He blinked, crawled out of his own head, and looked to see who was intruding. It was Archie.

"I was thinking," Sherlock protested.

"Yeah, I noticed, you zombie. But I've got the crime-scene photos. Copies of them, at least. Lestrade's got the originals."

"What took so long? Hasn't Lestrade heard of one-hour photos? At least the copies are in color. They are, aren't they?"

Archie opened the manila envelope that contained the fat stack of copied photographs. "They're in color."

"At least he did that right. Here, spread them out."

"On the dead guy's table?"

"You're right, not enough room. On the floor. Move the table out of the way first."

Archie did as he was told and dragged the table to the far end of the kitchen. Luckily, the garroter was single and for obvious reasons didn't entertain very often, and thus didn't feel the need to own King Arthur's Round Table. One person was able to move his furniture with relative ease.

While Archie rearranged the furniture, Sherlock remained in his chair. He'd dived back inside his head, and was oblivious to the scraping of the table's legs dragging along the floor. He was too busy mentally inventorying and reassembling the bomb to pay attention to ear-gouging noises.

"Happy?" Archie asked. Sherlock was mute and Archie rolled his eyes. He grabbed the manila envelope from Sherlock's lap and spread the photographs out at the great if somewhat infuriating detective's feet. Once he was done, he shook Sherlock's shoulder. Sherlock blinked, noted the photo spread, and slipped from his chair to get a closer look.

Archie returned to his chair, an island in a sea of gruesome pictures. This was beyond him. Not counting the first victim, he'd never investigated a bombing before, and while he'd managed to form a loose mental image of the bomb thanks to Sherlock's help, he had nothing else to go on. Everything about the bomb was generic, all the hardware untraceable, and any physical evidence the bomber might have left on the explosive or in the garage had gone up in smoke.

"Remove the bomb from the equation," Sherlock said. He gathered up every picture that featured a fragment of the bomb, or the cataclysmic damage it had wrought.

"But it's the entire equation," Archie replied.

"And it's useless. We aren't dealing with a madman who's going to send us a manifesto and practically catch himself. This is a professional. The bomb's got nothing more to tell us. We need to look elsewhere."

"Elsewhere" consisted of the meager remaining photographs, most of which were of the only tangible evidence, besides the bomb, that the killer had left: a long trail of footprints. The garroter had taken a big risk, living among the sheep, but in doing so, he'd made it more inconvenient for his assassin. Not inconvenient enough, obviously, but the bomber couldn't just park in the garroter's driveway, where the neighbors would all remember a strange car and person arriving in the night. They'd been forced to pull their car off the road, hide it behind a copse of trees, and then sneak the bomb across open ground. They'd managed in the end, but there was no hiding the track-way they'd created.

The police had photographed any footprint they'd found, and these photos Sherlock laid out in consecutive order. Sherlock ran his eyes up and down the line of photos, willing one to jump out at him.

He'd gone over the entire track three times before he froze. He understood now why none of the pictures were leaping out at him. Because they _all _should have been.

There was something seriously wrong with the footprints. The tread of each shoe was jammed with tiny objects of varying shapes. Stones? No, the shapes were geometric, man-made.

"Beads," Sherlock muttered.

"What?"

"Lestrade? Where the bloody hell is Lestrade?" Sherlock roared.

The inspector hurried into the room. "What... What did you do to the table?"

"That's not important! Did the police raid any street peddlers yesterday, specifically any involving jewelry?"

"That's not really my division," Lestrade replied.

"Find out!"

Lestrade made a few calls and within minutes had a reply.

"No, there were no raids, but there was an altercation involving a vendor and a tourist. The tourist made a mess of the vendor's tables. The vendor sold homemade jewelry. Cheap stuff, you know, nothing worth much."

"And where was this?"

Lestrade provided an address in one of London's sleazier districts.

"That's where we'll find our bomber."

* * *

TBC


	4. Haber's Rule

_Thirty Minutes Later_

Upon returning to the police station, Lestrade commandeered the largest available conference room and all officers who weren't busy sifting through either the garroter's garage or his home. He seated himself at the head of the table, with Sherlock to his right, and Archie, none-too-happy about it, was sandwiched between the two cops who had been involved with the bead scuffle hours ago. Set out in front of everyone were maps, photographs, and aerial views of the street where the suspected bomber had set up shop.

"The economy's finally back on its feet, but this area's not gotten the news just yet. Most of these buildings are vacant, at least when it comes to legal and legitimate business," Lestrade explained, pointing out the desolate neighborhood.

"The bomber's in that one. But they park their car there, in that little alley," Sherlock said after one glance at the map.

"Uh, right, there you have it. I don't know exactly how you have it, but-"

"It's the only scenario that makes sense. There is one building closer to the alley, but it's in shambles. A strong wind, never mind a small explosion, could demolish it. As for the car, there's no door large enough in that building to admit a car. Not that it matters. A car's a big, bloody petrol bomb, and accidents happen," Sherlock explained.

"But how do you know it's not a building further down the street?" a policewoman asked.

"Would you carry a bomb in public any further than necessary?"

"How do you know they were carrying the bomb at the time?"

"The shoes! Am I the only one who understands this?"

"But-"

"If your shoes were full of beads, you'd stop and pick them out. Unless you had something very important to do, and were under strict time restraints. Such as rigging a serial killer's garage to explode before he returned."

"So they just carried the bomb where anyone could see?"

"You're hopeless," Sherlock muttered.

"They had a backpack or something similar. Right?" Lestrade asked.

"Thank you!"

"Alright, mystery solved. We now have an address for this maniac, so let's get the bomb squad in here, brief them, and keep anything else from blowing up!"

While the police scrambled about, making all the necessary preparation for a tactical strike against a terrorist who was holed up in London, Sherlock cut through the crowd. He grabbed Archie and led him out of the room.

"Where are we going?" Archie asked.

"To Lestrade's car."

"Why?"

"Because he won't let you come otherwise."

"Oh."

* * *

_Twenty Minutes Later_

"Neither of you leave the car! I mean it! I don't care if the bloody ghost of Osama bin Laden appears! You! Stay! Here!" Lestrade shouted.

"You've locked the doors," Sherlock pointed out.

"And you've handcuffed Sherlock," Archie added.

"And the only reason I didn't handcuff you as well is because this is my last pair, and I may need it."

"I don't see why you're so upset. A living person is not the worst thing I've smuggled into a police vehicle," Sherlock said.

If Lestrade hadn't needed his hands for steering, he would have tried to strangle Sherlock. "Why do you think it's fine to bring a minor to a raid against a bomber? How does that sound like an appropriate field trip to you?"

"He's been to other crime scenes."

"Not ones where he could be blown to smithereens!"

"I didn't suggest we send him in to disarm any bombs by himself."

"That doesn't matter! Children don't belong here!"

"He's not a child!"

"In the eyes of the law he is! He's not John bloody Watson! He hasn't got military experience! He can't defend himself if something awful happens. And, maybe you didn't realize this Sherlock, but awful things happen around you!"

Sherlock's eyes narrowed. "Is it my fault Moriarty's sponsoring a competition between assassins? Or that people kill each other over pocket change? Or that-"

"I'm sorry, that's not what I meant. I wasn't blaming you. I only meant you have a dangerous job, and Archie may not be the best assistant."

Sherlock shook his head. Archie was likely more capable than either he or Lestrade suspected, or wished him to be.

"He'll be fine. I won't let anything happen to him," Sherlock said.

"I know you won't. And that's why you're staying in the bloody car."

Lestrade pulled the car to the side of the road. Behind him, the rest of the police forces did the same. It would be foolish and incredibly dangerous to pull up, sirens blaring, to the bomber's front door, so the plan called for them to park blocks away, set up a perimeter, scope out the situation, and allow the bomb squad ample room to do its job.

"Stay," Lestrade repeated one last time before exiting the car and going to meet his officers for a final rundown.

"Do they have a bomb-diffusing robot?" Archie asked.

"Yes, but I don't think it's going to be much use here. This is a terrorist who knows how to rig a trap even an intelligent human can't recognize until it's too late. A robot with a clumsy pincer isn't going to sort it out."

"So the bomber's got the place booby-trapped, you reckon?"

"Absolutely."

"Still hope I see that robot."

"I wouldn't be surprised if they use it for reconnaissance. It's got a camera on it, so they can peer into windows with it."

Archie pasted himself to the rear window. If they brought out the robot, nothing would keep him from seeing it.

Except maybe a massive explosion.

It felt like the world was shaking itself apart. Archie threw himself onto the floor and covered his head. In the front seat, Sherlock was stunned by the concussive shock-wave. The sound and energy were as physical a force as a kick to the gut. The psychological horror that accompanied a very big blast was almost as paralyzing.

After a moment of terrible silence following the blast, Archie lifted his head. "Sherlock? What happened?"

Sherlock shook his head, trying to clear the ringing in his ears. He could hear Archie, and the shouts of Lestrade's officers as they poured from their vehicles, but it was almost like hearing them underwater. Oh well. A little hopefully temporary hearing loss was, at worst, a minor distraction. Sherlock had investigated while suffering far worse.

Out of respect for Lestrade, Sherlock hadn't shucked out of the handcuffs while the inspector had been present, though he had been capable of doing it at anytime. Handcuff locks were some of the most primitive locks out there. Fishing out a wire he'd secreted in a seam in his coat-sleeve, Sherlock had both cuffs open in a matter of seconds.

"You've got to teach me how to do that," Archie said as he watched Sherlock outperform Houdini's greatest escapes.

Sherlock didn't reply. Instead, he unlocked the doors. No, Archie realized when he went for his door and still found it locked. Sherlock had only unlocked one door.

"You can't leave me here." Archie knocked on the Plexiglas partition that separated the back seat, and the criminals that were usually detained there, from the front seats. "Sherlock, come on."

Sherlock opened his door and stepped out into the chaos. The air was choked with dust by now, dust thicker than the meanest London fog, and within a few footsteps, the consulting detective had vanished.

The air was as full of noise as it was full of dust and smoke. Sirens blared, and underneath their din came the voices of dozens of men and women. Cops were bumping into each other in the murk, and Sherlock was flying as blind as the rest of them.

"Have you seen Lestrade?" Sherlock asked a man wearing the heavy body armor of the bomb disposal squad.

"Up ahead, I think," the man replied.

"Do we know the extent of the damage?"

"Can't see a thing yet. We'll have to let the dust settle and the fire brigade spray the whole bloody building."

Sherlock nodded and forged ahead. He began to notice debris scattered on the road. This far from the blast, most of the debris was small chunks of brick, stone, or other fragments of the building. As he approached the scene, the debris grew larger. Fist-sized pieces capable of killing someone were strewn about. It was in this striation that Sherlock bumped into Lestrade. Literally bumped into him. Lestrade's formerly navy jacket was so coated with dust he was like a chameleon in the grey atmosphere.

Lestrade turned around. "Sherlock? I can't say I'm surprised."

"Neither can I."

"I assume you mean about all this." Lestrade motioned with his arm to the impenetrable dust cloud.

"Yes. I expected a trap, but not one that would be sprung until it had the opportunity to cause massive casualties."

"So what happened, then? Terrorist use too short a fuse? Malfunction?"

Sherlock considered. "Or a trap not meant for us. Meant for someone more important."

"Like who, the Prime Minister? I doubt he'd be skulking around abandoned buildings. Then again, that is where they caught the last one meeting his ladies of the night."

"We changed Prime Ministers recently?" Sherlock asked.

Lestrade sighed. "About a year ago. Enormous scandal, prostitution ring, none of this rings a bell?"

"I was occupied with the case of the vanishing racehorse."

"Right, I remember that one. The horse was stolen by its own owner, and then hidden in plain sight."

"An excellent use of deception, and an equally excellent understanding of human nature. Ah!" Sherlock exclaimed.

Lestrade jumped. "What?"

"That's what we've got here. Deception. That bomb wasn't meant for us, I'm sure of it now."

"Then who was is meant for?"

"Another chess piece."

"You mean another killer? Which one?"

Sherlock began to pace, his coat cutting eddies into the dust cloud. "Which one, which one, which one..."

He suddenly snapped his fingers. "Besides the police and bomb squad, were any other emergency services notified?"

"The fire brigade, for obvious reasons. And ambulances. Again, for obvious reasons."

Sherlock nodded. "There you have it."

"One of the killers was a firefighter? Oh, of course. Firefighters sometimes use axes, and two of the victims were killed with cutting weapons. But was it the beheaded man, or the one cut into pieces? How sharp are those axes?"

"No! One weapon was obviously a machete, and the other a sword, likely a katana. Didn't you read my blog on wound patterns and cutting weapons? An ax wound doesn't look remotely like a sword, knife, or machete wound."

"I must have missed that one," Lestrade muttered. Trying to read Sherlock's blogs was like trying to read an encyclopedia article written in archaic English by an author who had never actually had a conversation with another human being. And who was fond of throwing graphic crime scene photos willy-nilly, which might explain why no human being wanted to talk to him. John's blogs were much more accessible, and tended to lack intimate details on how a three-day-old spleen smelled after sitting in a refrigerator.

Lestrade shook his head. "So it wasn't a member of the fire brigade, I take it. That leaves, what, a paramedic? A killer paramedic? Really?"

"Doctors and nurses have a storied history of murder. One of the most prolific serial killers of all time was a British doctor. It's about time paramedics decided to participate," Sherlock replied.

"That's perverse, Sherlock."

"No, it's logic. We have a victim killed by poison and bearing no defensive wounds. And then we have an explosion triggered by-"

"We don't know what triggered the explosion. Maybe the bomber made a mistake, or used a defective timer. These things happen."

"Five quid."

"Five quid for what?"

"Five quid says they find the body of a paramedic in the rubble."

Lestrade took a deep breath, closed his eyes, and then punched Sherlock in the face. Sherlock stumbled backwards, tripped over a warped piece of metal that once might have been part of a support beam, and fell into the dust.

A silence settled over the pair. Lestrade lowered his arm and unclenched his fist. As though worried his arm would act out again on its own volition, he hastily tucked his hand into his pocket. Sherlock stayed where Lestrade had put him. The consulting detective could feel blood on his nose and lips, and a quick flick of his tongue confirmed it.

Without a word, Sherlock sat up and wiped his face with the back of his hand. Already dust was settling into the blood, turning it brown and tacky. Lestrade winced as Sherlock smeared the mixture of blood and dust across his cheek, without actually removing very much of it. What little he did transfer to his hand didn't look any more pleasant in its new home.

"Here," Lestrade said, handing Sherlock a tissue. "I- I didn't mean it."

"Yes, you did mean it." Sherlock accepted the tissue and pressed it against his nose. "And I deserved it. If John was here, he'd agree with you."

"Even if you did, I can't go around punching people who upset me. I'm a public servant, and you're part of the public."

Sherlock's reply was interrupted by a squawk from Lestrade's radio. He unclipped the radio and said, "Repeat that, please."

"The fire brigade's here, but they can't see any better than we can," the radio voice said.

"They can find the road and drive straight, can't they?" Sherlock asked.

"I'm sure they can, Sherlock," Lestrade said, covering his radio so the voice on the other end wouldn't hear Sherlock. The detective inspector then removed his hand and said, "Clear everyone out of the road. And move any vehicles that are creating a blockade. The building's straight ahead, they can't miss it."

While other police moved invisibly through the dust, removing themselves and any errant vehicles from the fire engines' path, Lestrade took up his burden. Sherlock was sitting in the middle of the road, pinching the bridge of his nose and snuffling as the dust he breathed turned the blood in his nose to concrete. The consulting detective, despite it being his own words that had allowed the fire engines to move towards the still-unseen disaster, was in no great hurry to stand up.

"Sherlock, we've got to get off the road," Lestrade said.

"I can't breath through my nose," Sherlock replied.

"We can sort that out when you're not in danger of being run over."

Sherlock blew his nose loudly. Lestrade rolled his eyes.

"If that's the way you want it, fine." Lestrade grabbed Sherlock under the armpits and dragged him over the curb. Sherlock was unfazed by the treatment, or the bump of his tailbone against the curb, and continued to try to open his nasal passages.

Once Sherlock was safely out of the way, Lestrade got back on his radio. "Is everyone off the road?"

Since no cops, unless they'd gravitated into groups like rocks in the early days of the solar system, could see the position of anyone else, there was a long chain of "all clear" and "good here" and "bugger all if I know, I can't see my hand in front of my face."

Lestrade sighed. "Alright, that was useless. How about this? Anyone still _on_ the road, get yourself off, because the fire brigade's coming through!"

From the murk came disembodied chuckles that really were quite creepy. The policeman who'd initiated the call relayed that he'd gone ahead and given the fire brigade the go-ahead. He then added that the engines were going to go much slower than they liked, so they wouldn't run over anyone or anything that had somehow failed to heed all warnings.

Minutes later, the first fire engine rolled past Lestrade and Sherlock. Sherlock waved to it, like he was watching a parade. Lestrade decided to be a little more attentive, and stepped forward to meet the engine.

The firemen were wearing respirators, and Lestrade wondered briefly what exactly was floating around in the dust he'd been breathing unprotected for more than twenty minutes. Then he shook the thought away. Now wasn't the time to worry about it, and he could snag surgical masks from an ambulance once he knew the fire brigade was safely onsite.

"It's like the Great Smog of 1952!" the driver said.

Lestrade nodded. "My granddad loved to tell me about that."

Pleasantries out of the way, the detective inspector and the fireman exchanged what little information they had about what had happened. The firemen inside the engine both winced when Lestrade confirmed the explosion hadn't been a gas leak or other accident, but had been triggered by the bomber. They became even grimmer when Lestrade told them there was possibly at least one body in the rubble. He didn't specifically mention that the body would belong to a paramedic, but Sherlock was satisfied enough not to correct him.

Once the exchange was over, the fire engine continued its trudging drive to its final destination. Feet behind it, another engine followed, and behind that, a third provided back-up. Lestrade wouldn't be surprised if more engines filtered in. _Everyone_ responded to threats of terrorism and came to do their part, even if they had to drive all the way across the city to do it.

Lestrade turned to Sherlock. "We should get out of this dust. Come on, Sherlock, there's nothing more we can do until the air clears and the fire brigade does its duty."

Sherlock hopped to his feet. Even with the tissue, he hadn't made much headway against the blood now caked to his face like peeling wall plaster. Lestrade saw this and winced. He hoped he had a bottle of water in the car, and if not, he hoped it wouldn't be long before he could get a protective mask over Sherlock's face and hide what he couldn't properly clean up.

"It's not broken, is it?" Lestrade asked as he and Sherlock floundered through the dust.

"Don't think so," Sherlock replied. "It's stopped bleeding, at least."

"Probably stuffed with dust."

"I've had it stuffed with worse."

"I don't know how to take that."

Sherlock smirked. "I don't mean drugs...or do I?"

"I am not afraid to bust your flat again."

"Oh goody, you can play hide and seek with my new shrunken head."

Lestrade barely suppressed a shudder. The legality of at least some of the contents of Sherlock's flat had to be called into question, but nobody in the police force was all that eager to look for an answer.

They finally arrived back at the car, which had accumulated years' worth of dust in under half an hour. Lestrade silently wondered how long it would take to get the dozens of involved vehicles clean again. Sherlock could probably, in seconds, calculate it, but Lestrade was dreading the sum.

Lestrade opened his door and swore when he noticed how much dust was already in the car. How had that happened? Had he left a window down or had it all wormed through the vents or-

"Sherlock, what's wrong?"

Sherlock had made no attempt to get into the passenger's seat, but was instead standing on the side of the road, staring at the car.

"Shit." Lestrade forgot all about seeking refuge from the dust and joined Sherlock outside. "What's happened? Oh, bugger."

The left window in the back seat had been smashed completely. Lestrade turned to Sherlock.

"Archie's done a runner."

"He had help. The glass is all inside the car. He couldn't have kicked the window out; someone else struck it from the outside," Sherlock replied.

"Maybe he called for help, and one of the officers-"

"Didn't bother to try the front doors before smashing the window of their boss' car?"

"We're only human, Sherlock, we panic when things blow up."

Sherlock shook his head. "Look at the footprints."

Lestrade looked down. There was a stampede of prints of all different sizes preserved in the dust, but two of them instantly stood out. They weren't typical police boots. One of them was a pair of sneakers with the logo in the tread, and the other Lestrade couldn't identify.

"Following footprints. That's really basic police work," Lestrade said as Sherlock led the way.

"Sometimes the old ways are the best," Sherlock replied. The footprints were occasionally overrun and obscured by cops' prints, but never so badly Sherlock lost the trail. The dust might have been hell on everything else, but it did facilitate tracking.

The trail quickly broke away from the heavy concentration of police activity, and Lestrade swore under his breath. This wasn't looking good. A cop would check on Archie, make sure he was alright, but then they'd stash him in another car, and radio to let Lestrade know about the property damage. They wouldn't take Archie up a dark alley and-

Sherlock came to a sudden halt and Lestrade almost bumped into him. When Sherlock showed no sign of moving, Lestrade stepped around him and saw instantly what had frozen Sherlock in his tracks.

There was a body sprawled out just ahead of them.

* * *

TBC


End file.
